The present invention relates to compounds useful as cannabinoid receptor ligands and, more particularly, to compounds that bind to cannabinoid (CB2) receptors. Compounds according to the present invention can exhibit anti-inflammatory and immunomodulatory activity and are useful in treating conditions characterized by inflammation and immunomodulatory irregularities. Examples of conditions which may be treated include, but are not limited to, rheumatoid arthritis, asthma, allergy, psoriasis, Crohn's disease, systemic lupus erythematosus, multiple sclerosis, diabetes, cancer, glaucoma, osteoporosis, renal ischemia, cerebral stroke, cerebral ischemia, and nephritis. The invention also relates to pharmaceutical compositions comprising one or more compounds according to the present invention, and methods of treating cancer, inflammation, immunomodulatory conditions, and respiratory diseases with such compounds.
Cannabinoid receptors belong to the superfamily of G-protein coupled receptors. They are classified into the predominantly neuronal CB1 receptors and the predominantly peripheral CB2 receptors. While the effects of CB1 receptors are principally associated with the central nervous system, CB2 receptors are believed to have peripheral effects related to bronchial constriction, immunomodulation and inflammation. As such, a selective CB2 receptor binding agent is expected to have therapeutic utility in the control of diseases associated with inflammation, immunomodulation and bronchial constriction such as rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, diabetes, osteoporosis, renal ischemia, cerebral stroke, cerebral ischemia, nephritis, inflammatory disorders of the lungs and gastrointestinal tract, and respiratory tract disorders such as reversible airway obstruction, chronic asthma and bronchitis (see, e.g., R. G. Pertwee, Curr. Med. Chem. 6(8), (1999), 635).
Various compounds have reportedly been developed which interact with CB2 receptors and/or which have, inter alia, anti-inflammatory activity associated with cannabinoid receptors. See, e.g., U.S. Pat. Nos. 5,338,753, 5,462,960, 5,532,237, 5,925,768, 5,948,777, 5,990,170, 6,013,648 and 6,017,919.